Hide subtitle for dialog from QS when applicable

- Always show device management subtitle
- Hide subtitle for others (vpn/network monitor/ca) if there is only 1
message
- Show subtitles if there are multiple messages

screen shots of a few combinations of conditions

device management + vpn
https://hsv.googleplex.com/5171127252942848

device management
https://hsv.googleplex.com/5156831890505728

vpn
https://hsv.googleplex.com/4788656657137664

ca + vpn
https://hsv.googleplex.com/6238262343499776

ca
https://hsv.googleplex.com/5725008114483200

ca + network log
https://hsv.googleplex.com/5145599846383616

network log
https://hsv.googleplex.com/5124533736439808

Bug: 64555046
Test: hard coded valued for each condition
Test: runtest --path frameworks/base/packages/SystemUI/tests/src/com/android/systemui/qs/QSSecurityFooterTest.java
Change-Id: Id9fcd8f0727eb2d40338c8c0d6530ab576f7b310